Color photographic light sensitive materials having improved light fastness

ABSTRACT

A COLOR PHOTOGRAPHIC LIGHT SENSITIVE MATERIAL COMPRISING A SUPPORT AND A PHOTOGRAPHIC LAYER CONTAINING A COMPOUND REPRESENTED BY THE FOLLOWING FORMULA:   1-(R-O-),4-(R&#39;&#39;-OOC-C(-CN)=CH-)BENZENE   WHEREIN R AND R&#39;&#39;, WHICH MAY BE THE SAME OR DIFFERENT, REPRESENT AN ALKYL GROUP HAVING FROM 1 TO 20 CARBON ATOMS, THE SUM OF THE CARBON ATOMS OF SAID R AND R&#39;&#39; BEING AT LEAST 5.

Dec. 26, 1972 REIICHI OHI ET AL 3,707,375

COLOR PHOTOGRAPHIC LIGHT SENSITIVE MATERIALS HAVING IMPROVED LIGHT FASTNESS Filed Oct. 7, 1970 TRANSMISSION WAVE LENGTH WAVE LENGTH INVEIVCRS REHCHI OHI TOK IHARU KONDO KAZUO SHIRASU YOSHIAKI 0N0 BY 74m! 10M, Z; 4 MaK ATTORNEYS United States U.S."Cl. 96-84 R 10 Claims ABSTRACT OF THE DlSClLOSURE A color photographic light sensitive material comprising a support and a photographic layer containing a compound represented by the following formula:

-0-12 7 V t) wherein R and R, which may be the same or different, represent an alkyl group having from 1 to 20 carbon atoms, the sum of the carbon atoms of said R and R being at least 5.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to a color photographic light sensitive material having improved fastness to light.

Description of the prior art Since a color photographic image is composed of dyes formed by color development, the image is inferior in light fastness to a black and white photographic image made of metallic silver. It is considered conventional to obviate this disadvantage by removing the influence of ultraviolet rays which tend to destroy the dyes of the color image by utilizing an ultraviolet absorbent. Various methods have been proposed along these lines in which ultraviolet absorbents which will not be removed during development processing are incorporated into the light sensitive materials during the production thereof.

The ultraviolet absorbents used for this purpose are required to have the following properties:

(1) They must effectively absorb ultraviolet rays having wave lengths of 300-400 millimicrons, but not visible light having wave lengths longer than 420 millimicrons;

(2) They must not be removed or disordered by development;

(3) The ultraviolet absorbents themselves must not be colored or undergo a decrease in their ultraviolet absorbing powers by exposure to light; and

(4) They must not deleteriously influence the photographic light sensitive materials during production thereof, preservation or development.

Many kinds of ultraviolet absorbents are presently known but few satisfy all of the above-mentioned factors. Further, many of the commercially-available ultraviolet absorbents are washed out or discolored and some deleteriously influence the photographic properties of the photographic light sensitive emulsions.

As a method of avoiding the bad influences of ultra violet absorbents on photographic silver halide emulsions, a method is known wherein a water-insoluble ultraviolet absorbent is dissolved in a water-insoluble high boiling organic solvent, such as dibutyl phthalate, and then added to a photographic silver halide emulsion as an emulsified atent O "ice dispersion (e.g. see US. Pats. Nos. 2,739,888 and 3,352,681).

As a result of various investigations, the present inventors have turned their attention to incorporating in a photographic silver halide emulsion a water-insoluble oily ultraviolet absorbent as an emulsified dispersion and have searched for ultraviolet absorbents suitable for this purpose. Furthermore, such ultraviolet absorbents must be, in addition to satisfying the above-mentioned requirements, oily materials capable of being dispersed in a gelatin sol as a stable emulsified dispersion. With these considerations in mind, the'present inventors have synthesized various compounds and have discovered the compounds represented by the following general formula to be suitable for these purposes:

(H3O-R' 0 wherein R and R, which may be the same or different,

represent an alkyl group having l-2() carbon atoms, the sum of the carbon atoms of said Rand R being at least 5.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the spectral transmission curve of a gelatin film containing the ultraviolet absorbent of the present invention; and

FIG. 2 represents the spectral sensitivity curves of three samples which do not contain the absorbent of the present invention (curve 1), which do contain the absorbent of the present invention (curve 2) and which contain a conventional absorbent.

DESCRIPTION OF THE PREFERRED EMBODIMENTS When the above compound is added to an aqueous gelatin solution containing a surface active agent and the mixture is treated in a colloid mill, a stable emulsified dispersion can be obtained and by applying the gelatin sol containing the above-mentioned ultraviolet absorbent to a color photographic light sensitive material as a subsidiary layer, such as a protective layer, an intermediate layer, and under-coat, or a backing layer when a transparent support is used, the light fastness of the color photographic image can be improved.

Since the use of the ultraviolet absorbents of this invention does not require a solvent for the emulsified dispersion of the compound, the amount of gelatin to be used for emulsifying the dispersion can be reduced, which makes the coating and drying processes economically profitable as well as effectively improving the sharpness of the color photographic image and the speed of the developing process due to the reduced thickness of the coated layers. Moreover, if necessary, the dispersion containing the ultraviolet absorbent of this invention may be incorporated in the photographic silver halide light sensitive emulsion layers and when employed in this manner, the ultraviolet absorbents of this invention do not adversely influence the photographic properties of the silver halide emlusion layers.

Usually, the application of an ultraviolet absorbing layer is accompanied by a reduction in the visible light sensitivity of a blue-sensitive emulsion layer. However, when the ultraviolet absorbent of this invention is used, the sensitivity of the blue-sensitive layer is not reduced since the compound absorbs almost no visible light, and also, the sensitivity of the blue-sensitive emulsion layer to ultraviolet rays can be cut sharply. In addition, by cutting the sensitivity of the blue-sensitive emulsion layer to ultraviolet rays, the quality of the color reproduction based on the difference in ultraviolet absorption characteristics of the camera lens can be reduced.

The above-mentioned characteristics of the ultraviolet absorbents of this invention will become apparent by reference to the accompanying drawings.

FIG. 1 shows the spectral transmission curve of a gelatin film containing an emulsified dispersion having incorporated therein the ultraviolet absorbent of this invention in an amount of 20 mg. per 100 cm. and as shown in the graph, it exhibits sharp absorption characteristics at 390- 400 millimicrons.

FIG. 2 is a graph showing the spectral sensitivity curves of (1) A sample in which no layer containing the ultraviolet absorbent of this invention is formed on a bluesensitive emulsion layer (curve 1), a

(2) A sample in which a layer containing the ultraviolet absorbent of this invention is formed thereon (curve 2, and

(3) A sample in which a layer containing a known ultraviolet absorbent, 3-cetyl-5-benzal-3-phenyliminothiazolidone is applied onto a blue-sensitive emulsion layer (curve 3). Each sample was exposed by means of a spectrophotometer and subjected to color development. As shown by the results in FIG. 2, it will be understood that in the sample having the layer containing the ultraviolet absorbent of this invention, the sensitivity in the ultraviolet region was cut sharply without reducing the sensitivity thereof in the visible region.

Since the compound of this invention is an oily material, the compound can be used as a solvent for various substances that are added using a high boiling point organic solvent such as dibutyl phthalate, for instance oily couplers, antioxidants, and solid ultraviolet absorbents other than those of this invention. Also, as the case may be, the ultraviolet absorbents of this invention may be used together with a high boiling point organic solvent.

The amount of the compound of the present invention to be used in color photographic material may be appropriately selected by those of ordinary skill in the art as is conventional. Generally, the ultraviolet absorbent of the present invention is employed in an amount of from 1 to 100, preferably 5 to 30, mg. per 100 cm. of the layer containing the compound.

In any event, the use of an oily ultraviolet absorbent in color photographic light sensitive materials gives superior results when compared to the use of ultraviolet absorbents which are solid at about room temperature the oily absorbent being employed as a solution in a high boiling point organic solvent.

Shown below are typical examples of the compounds of this invention represented by the above-mentioned general formula, together with their boiling points.

Compound 1 B.'P. 185-188 C./O.4 mm. Hg

RP. l91l92 C./0.38 mm. Hg

Compound 3 B.P. 198-220 C./0.24 mm. Hg

Compound 4 B.P. 2432S3 C./2.4 mm. Hg

Compound 5 Compound 6 B.-P. 220-225 C./0.3O mm. Hg

These compounds shown above may be synthesized from the corresponding cyanoacetic esters and alkoxybenzaldehydes by ordinary methods (see, e.g., Beil. vol. 10, p. 521).

An example of synthesis is illustrated as follows: to 500 ml. of benzene was added 136 g. of anisaldehyde, 197 g. of 2-ethylhexyl cyanoacetate, 10 g. of ammonium acetate and 25 ml. of glacial acetic acid. The mixture was heated at l30-l40 C. while stirring to completely distill off Water. After the reaction, 300 ml. of benzene was added. The benzene solution was washed with water, dried and the benzene distilled off. The residue was distilled under reduced pressure to obtain 270 g. of Compound 3 having a B.P. of 198-220 C./0.24 mm. Hg.

It is known that compounds similar to the compounds of this invention are useful as ultraviolet absorbents (see e.g., German Pat. No. 1,087,902) but there is no prior art practically describing the compounds of this invention which are particularly useful as ultraviolet absorbents for color photographic light sensitive materials. Furthermore, the compounds disclosed in the above-mentioned German patent are solids at normal temperature and are thus less unsable for our purposes.

The invention will now be explained in detail by the following non-limiting examples.

As shown in the above table, 50 g. of Compound 2 is directly added to a mixture of 1 kg. of a 10% aqueous gelatin solution and 50 ml. of 5% sodium dodecylbenzene sulfonate and the mixture is dispersed by emulsification for 5 minutes in a colloid mill. Then, the mixture is coated onto a triacetyl cellulose base and dried to provide a sample which is called Sample A.

Then, 50 g. of Compound 2 of this invention is mixed at room temperature with 50 ml. of dibutyl phthalate and after the mixture is emulsified and dispersed into the mixture of the aqueous gelatin solution and the sodium dodecylbenzene sulfonate as above, the resultant mixture is coated onto a triacetyl cellulose film and dried to provide a sample which is called Sample B.

For comparison, 50 g, of a known ultraviolet absorbent, 3-cetyl-5-benzal-3-phenyliminothiazolidone, that thas ultraviolet absorption characteristics similar to those of Compound 2 of this invention, is mixed with 50 ml. of dibutyl phthalate followed by dissolving under heating, and after being dispersed by emulsification as above, the resultant mixture is coated onto a triacetyl cellulose film and dried to provide a sample which is called Sample C.

These samples were compared as follows: Sample C is transparent directly after coating but when the sample stands at room temperature for about one month, crystals are formed and the coated layer containing the known ultraviolet absorbent becomes a opaque. Such crystalliza tion is also formed within one day when the layer is rubbed or otherwise subjected to an impact. On the other hand, Samples A and B do not undergo these disadvantageous phenomenon. Also, when the mixture of Compound 2 and dibutyl phthalate was heated during the production of Sample B, the properties of Sample B were not changed or reduced. Incidentally, when the mixture of dibutyl phthalate and the known ultraviolet absorbent, 3cetyl-5-benza1-3-phenyliminothiazolidone is not heated, the ultraviolet absorbent is not dissolved in the solvent.

Each sample was then exposed to a fluorescent lamp of 10,000 lux for 14 days and the reduction ratio in absorption maximum is shown in the following table.

Reduction ratio in absorption maximum (percent) Sample A 29 Sample B 31 Sample C 30 Also, when each of the samples is stored under conditions of 60 C., a relative humidity of 70% for 14 days; 40 C., a relative humidity of 90% for 14 days; and 80 C. for 7 days without light exposure, no reduction in absorption maximum is observed in each case. Moreover, when Samples AC are subjected to the following processing (at 30 C.) by the solutions described in The British Journal of Photography; Sept. 27, p. 838 (1968), no reduction in absorption maximum is observed in each sample:

Minutes Development 7 Stop fixing 2 Water washing 2 Bleaching 2 {Water washing 2 Hardening fixing 2 Water washing 4 Stabilization 2 Further, the same procedures as in the production of Sample A and Sample B were followed using Compound 1, and Compounds 3-5, and almost the same results were obtained.

EXAMPLE 2 Onto a baryta-coated paper are coated a blue-sensitive silver iodobromide emulsion containing benzoylaceto-Z- chloro-S-dodecylcarbonyl anilide as a yellow coupler, a gelatin sol as an intermediate layer, a green-sensitive silver chlorobromide emulsion containing 1-phenyl-3-[3-N- butylcaprylamidopropionarnido]-5pyrazolone as a magenta coupler, a gelatin sol as an intermediate layer, and a red-sensitive silver chlorobromide emulsion containing l-hydroxy 2 [3-{2',4-t-aminophenoxy}propyl]naphthamide as a cyan coupler, in that order. Each of the couplers was added to the respective photographic emulsion by dissolving the coupler in dibutyl phthalate, emulsifying the solution in an aqueous gelatin solution, and then adding the emulsified dispersion to the photographic emulsion.

Thereafter, an emulsified dispersion corresponding to each of Samples A-C as prepared in Example 1 is applied to the red-sensitive emulsion layer as a protective layer so that the proportion of the ultraviolet absorbent becomes 20 mg./ 100 cm The color photographic light sensitive film having the protective layer of Sample A in Example 1 (using no dibutyl phthalate) is designated Sample D; the color photographic light sensitive film corresponding to Sample B is designated Sample E; and the color photographic light sensitive film corresponding to Sample C is designated Sample F. Also, for comparison, a color photographic light sensitive film having a protective layer consisting of only a gelatin sol is prepared and designated Sample G.

After comparing these samples, it was confirmed that Sample F readily crystallized and Sample C is thus not suitable for use as the protective layer, whereas no such trouble occurs in Samples D and E and hence Samples A and D, containing the ultraviolet absorbents of this invention, are particularly suitable for preventing fading of color photographic light sensitive materials.

When the sample films thus prepared are subjected to the photographic processings as shown in Example 1 and exposed to a fluorescent lamp of 10,000 lux for 14 days, the light fastness of Samples D and E, each having a protective layer containing an ultraviolet absorbent, is superior to that of Sample G as shown in the following table, in which the numerical values are fading ratios in percentage of color images at a density of 1.0.

Percent E F G However, although Sample F, directly after processing, is almost the same as the other samples, crystals are formed on the surface of the sample after 14 days, thereby matting the surface. Also, when the samples are preserved for 14 days at a temperature of 60 C. and a relative humidity of 70% and for 14 days at a temperature of 40 C. and a relative humidity of 90%, the extent of the change of the color image density is almost the same in Samples DG. However, under conditions of C. and 7 days, Sample F crystallized, whereas no change was observed in Samples D, E, and G.

In this experiment, the emulsified dispersion of the ultraviolet absorbent is used as is as the protective layer, and the dispersion may be added to a gelatin solution. Further, the same procedure as described above is followed using Compound 1, Compound 3, Compound 4, or Compound 5, and almost the same results are obtained as those of Samples D and E.

Also, when a transparent film is used in the above procedure instead of the baryta-coated paper, the same results are obtained.

EXAMPLE 3 Onto a triacetyl cellulose film are coated the blue-sensitive silver iodobromide emulsion containing a yellow coupler and the gelatin sol, as an intermediate layer, as shown in Example 2. Onto the intermediate layer is coated a red-sensitive silver chlorobromide emulsion containing an emulsified disperson having the following composition:

Further, onto the red-sensitive emulsion layer are coated successively a gelatin sol as an intermediate layer, a greensensitive silver chlorobromide emulsion containing a magenta coupler, and then a gelatin sol as a protective layer.

The emulsified dispersions having the compositions shown in the above table were prepared in the following manner. A solution of the cyan coupler and the ultraviolet absorbent in dibutyl phthalate, prepared by heating the mixture, is added to a mixture of 1 kg. of a 10% aqueous gelatin solution and 100 ml. of sodium dodecylbenzene sulfonate and then the resultant mixture is emulsified for 5 minutes in a colloid mill. As is clear from the above table, in case of Sample I wherein the cyan coupler is used together with the known ultraviolet absorbent, the amount of the solvent, dibutyl phthalate, must be increased in accordance with the amount of the ultraviolet absorbent to be added, whereas in case of Sample H wherein Compound 3 of this invention is used with the cyan coupler, the amount of the solvent can be reduced in accordance with the increase in the amount of the ultraviolet absorbent, which makes the present invention economically advantageous.

Then, when the samples are subjected to the photographic processings described in The Journal of the S.M.P.T.E., vol. 61, No. 12, 667 (1953) and then exposed to a fluorescent lamp of 10,000 lux for 14 days, it is confirmed that the color photographic film of this invention, where the coupler and the ultraviolet absorbent of this invention are simultaneously dispersed by emulsifying, exhibits an effective antifading effect as shown in the following table, in which the numerical values are fading ratios of the color images at a density of 1.0.

Also, when the samples are preserved for 14 days at a temperature of 60 C. and a relative humidity of 70%, for 14 days at a temperature of 40 C. and a relative humidity of 90%, and for 7 days at 80 C., each sample shows a similar change.

When the ultraviolet absorbent of this invention is dis persed by emulsifying together with a magenta coupler or a yellow coupler, effective results are obtained. Also, the ultraviolet absorbent of this invention can be used effectively in other photographic layers than as in the color photographic light sensitive material illustrated above.

From the above description, it is clear that when the emulsified dispersion containing the ultraviolet absorbent of this invention is added to a silver halide photographic emulsion layer or subsidiary layer such as a protective layer, an intermediate layer, an under-coat, and, when a transparent base is used, a back layer, the fading by light) of the color image of the photographic silver halide emulsion layer containing the ultraviolet absorbent of 111118 invention or the color image of a photographic silver halide emulsion layer covered by a layer containing the ultraviolet absorbent of this invention is effectively prevented.

What is claimed is:

1. A color silver halide photographic light sensitive material comprising a support and a sliver halide photographic layer and optionally, a subsidiary photographic layer, either of said layers containing a compound represented by the following formula:

wherein R and R, which may be the same or different, represent and alkyl group having from 1 to 20 carbon atoms, the sum of the carbon atoms of said R and R being at least 5.

2. The color silver halide photographic light sensitive material as claimed in claim 1, wherein said subsidiary photographic layer is a protective layer.

3. The color silver halide photographic light sensitive material as claimed in claim 1, wherein said subsidary photographic layer is a backing layer.

4. The color silver halide photographic light sensitive material as in claim 1 wherein said compounds is represent by the following formula:

5. The color silver halide photographic light sensitive material as in claim 1 wherein said compound is represented by the following formula:

6. The color silver halide photographic light sensitive material as in claim 1 wherein said compound is represented by the following formula:

7. The color silver halide photographic light sensitive material as in claim 1 wherein said compound is represented by the following formula:

8. The color silver halide photographic light sensitive material as in claim 1 wherein said compound is represented by the following formula:

9. The color silver halide photographic light sensitive material as in claim 1 wherein said compound is represented by the following formula:

10. The color photographic light sensitive material as in claim 1 wherein either of said photographic layer contains from 1 to rug/cm? of said compound.

References Cited UNITED STATES PATENTS 

